Mobility

Tunable, multi-dimensional separation of macromolecules and particles

The Mobility™, in conjunction with an Eclipse® DualTec® or Eclipse AF4 asymmetrical-flow field-flow fractionation (AF4) system, separates macromolecules and particles from 1 nm to 10,000 nm by size and charge.

enhanced separations of particles with the same size but different charge

true size / zeta potential distributions

The Mobility is invaluable for studying viral vectors, liposomal or polymeric drug delivery vehicles, colloidal stability of proteins and sub-micron particles, and a host of other macromolecules and colloids.

A new dimension in FFF

Standard field-flow fractionation using AF4 is a versatile, size-based separation technique that can
be tuned to adjust resolution and range. With no packed stationary phase, AF4 is free of shear, and
adverse surface interactions are minimal, making it an ideal technology for complex and difficult
analytical fractionation tasks.

The Mobility adds the ability to modulate separation by charge. Depending on the particle’s charge and
polarity, its motion under the electric field combines with AF4 cross flow and parabolic channel flow
to produce later or earlier elution. Hence analytes with the same size but different charge leave the
EAF4 channel and reach the detectors at different times. Each fraction is characterized separately by
the detectors.

Combining electrical fractionation with AF4 in a single separation channel in EAF4, the Mobility is
the most powerful and versatile separation technology available for macromolecules and nanoparticles
from 1 nm to 10,000 nm.

What's inside?

EAF4 combines conventional asymmetric-flow
field-flow fractionation with an applied electric field to separate particles by size and charge.

an EAF4 channel incorporating two electrodes with a standard AF4 frit and membrane

a conductivity cell and a pH cell

an electrode control unit.

These are used with a standard Eclipse FFF controller and HPLC components from Agilent, Shimadzu or Thermo.
Temperature control of the EAF4 channel is provided by a Thermos[Pro] chamber.

The electrodes, placed above and below the AF4 channel, create a programmable electric field but are never
actually touched by sample. These platinum-coated steel electrodes are compatible with a large range of salt
concentrations: they do not corrode, and the pressure present in the channel prevents bubble formation under
electrolysis.

Multi-dimensional separation

Determining zeta potential

Click to enlarge

SCOUT DPS - By running the sample at a series of applied electric fields and measuring the shift of elution
time with field, the zeta potential and hydrodynamic radii of particles of discrete sizes (that do not overlap in the fractogram)
are determined from EAF4 theory.

Resources

Wyatt Technology is the recognized leader in light scattering instrumentation and software for determining the absolute molar mass, size, charge and interactions of macromolecules and nanoparticles in solution.